The design rule of a semiconductor device is rapidly reduced as a semiconductor device not only tends to be compact, slim and lightweight, but is also highly integrated. Consequently, a channel between source and drain electrodes of a transistor can be shortened, which may cause short channel effects in a transistor, with the result that a gate control function may be reduced or lost.
It is known to use a recess channel array transistor (RCAT). The recess channel array transistor has a structure in which a channel of the transistor is lengthened by forming a recess channel trench in a region to be formed into the channel.
In a conventional method of fabricating such a recess channel array transistor, a hard mask pattern is formed on a substrate, a trench is formed in an active region of the substrate by using the hard mask pattern as an etching mask, the hard mask is removed, and then the trench is filled with an electrically conductive material to thereby form a gate.
The hard mask pattern may, for example, be formed in such a manner as to contain a material, such as silicon oxide, silicon nitride, etc. The hard mask pattern may also include a line pattern open area shaped similar to the gate. Thus, the open area of the hard mask pattern may expose part of an isolation region 101, as well as a part of the active region. The trench is formed by etching the active region exposed by the hard mask pattern, and the isolation region exposed by the hard mask pattern is also etched in the course of removing the hard mask pattern, on account of which a field recess may be formed. Subsequently, when the electrically conductive material is filled in the trench formed in the active region, the electrically conductive material may also be deposited in the field recess, so that the gate may be formed in the active and on isolation regions.
However, the gate formed on the field recess in the isolation region may cause coupling noise, resulting from the so-called passing gate effect, to a semiconductor device formed in the active region, which may degrade the characteristics of the semiconductor device.